Preparation and evaluation of lidocaine hydrochloride in cyclodextrin inclusion complexes for development of stable gel in association with chlorhexidine gluconate for urogenital use

Abstract

Luiz Francisco Jones Soares da Silva, Flavia Almada do Carmo, Vinicius Raphael de Almeida Borges, Lidiane Mota Monteiro, Carlos Rangel Rodrigues, Lúcio Mendes Cabral, Valeria Pereira de SousaDepartamento de Medicamentos, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, BrazilAbstract: Inclusions of lidocaine hydrochloride in cyclodextrins were prepared to obtain stable complexes compatible for association with chlorhexidine in a new gel formulation for use in urogenital applications. Two cyclodextrins, β-cyclodextrin and methyl-β-cyclodextrin, were used for encapsulating lidocaine hydrochloride through solubilization and kneading techniques. The lidocaine–cyclodextrin complexes were characterized by ultraviolet spectroscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, and X-ray diffraction. The results revealed that the techniques generated good yields of inclusion products that maintained the functional properties of lidocaine. In addition, the inclusion products obtained improved the compatibility of lidocaine hydrochloride with chlorhexidine in solution and a gel formulation. The gel formulation displayed desirable rheological and physicochemical properties. The results presented here are the first description of the inclusion of lidocaine with cyclodextrins, which improves compatibility with chlorhexidine in formulations for simultaneous delivery.Keywords: solubilization and kneading inclusion techniques, cyclodextrins, lidocaine hydrochloride, chlorhexidine gluconate incompatibility, urogenital gel formulations